The purpose of this research is to develop more efficient and selective routes to natural products or other medicinally relevant compounds containing stereogenic ketal or aminal structures. This work may affect several diverse areas of medicine including anticancer, antibacterial, antifungal, and antiviral therapeutics. The key technology platform this proposal builds on is anion binding catalysis with thioureas. This provides a method to catalyze SN1 substitution reactions with previously unattainable facial control. Given the lack of methods to access carbocations with any sort of catalyst control, this should have far-reaching impact on a variety of chemistries. Anion binding catalysis will primarily be applied to the enantioselective and diastereoselective synthesis of spiroketals/spiroaminals and sugars through O-glycosylation. These moieties are currently difficult to prepare with high levels of stereocontrol. PUBLIC HEALTH RELEVANCE: The purpose of this research is to develop new chemical reactions that can provide chemists with more efficient means to prepare potential drugs. This work may affect several diverse areas of medicine including anticancer, antibacterial, antifungal, and antiviral therapeutics.